Effect of Different Drying Methods on Antioxidant Compounds and Antioxidant Activities of Banana Inflorescence

• Main Authors: Fong-Yun Lin, 林鳳芸
• Other Authors: Tien-Tso Wu
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/81765896964753718025

碩士 === 大仁科技大學 === 食品科技研究所 === 99 === Banana (Musa sapientum) is one of important fruits in Taiwan. Because banana inflorescence will consume some nutrients during banana growth period, it is usually cut off as a fertilizer or a culinary ingredient. However, study on banana inflorescence is very rare so far. The aim of this study was to investigate the characteristics of anthocyanin in banana inflorescence and its stability after drying. The banana inflorescence was supplied by Taiwan banana research institute. The banana inflorescence was divided into two parts: bract and male flower. After different drying treatments, the pattern of anthocyanidins was determined by HPLC. The contents of β-carotene and lycopene were analyzed by LC/MS/MS. Total anthocyanin, monomeric and polymeric anthocyanins, caroteniod, polyphenol and flavonoid were measured by spectrophotometer. Antioxidant activities included DPPH radical-scavenging ability, reducing power, inhibition of lipid peroxidation and superoxide radical scavenging ability. The results showed that the contents of polyphenols and flavonoids in banana inflorescence decreased after drying treatments. The contents of polyphenols and flavonoids in banana bract treated by 55℃ hot-air and freeze drying were higher than that by 80℃. Both polyphenol and flavonoid contents of male flower obviously decreased by increasing drying temperature. It was found that more carotenoids and β-carotene remained in banana inflorescence after 55℃ hot-air drying than other drying methods. In this result, fresh banana inflorescence (bract and male flower) had higher content of total anthocyanins than dried inflorescence. The kinds of anthocyanidin in bract and male flower were different. The major anthocyanidin in bract and male flower was cyanidin and delphinidin, respectively. The color of banana bract was tending to dark red with increasing the total anthocyanin. The antioxidant activities of banana bract and male flower dried at 55℃ were better than that at high temperature (80℃). Scavenging activity of DPPH radical of banana inflorescence dried at 80℃ was lower than other drying treatments. Reducing power of bract treated by 55℃ hot-air and freeze-drying conditions was better than that by other drying temperatures. At high concentration (1000 ppm), male flower dried at 30℃ had the highest reducing power and the reducing power was the lowest at 80℃. Banana bract and male flower at 55℃ had better inhibition of lipid peroxidation. It was found that the contents of anthocyanins, polyphenols and carotenoids were significantly positive correlations with antioxidant activities. Between flavonoid content and antioxidant activities of male flower were significantly correlated. Since banana inflorescence has high moisture content, drying can extend its shelf life. This study suggests that either freeze-drying or 55℃ hot-air drying can be used as drying condition. Anthocyanin, antioxidant compound and antioxidant activity of banana inflorescence were obviously decreased by long time at low temperature (30 ℃) and short time at high temperature (80 ℃).